1. Field of the Invention
The present invention relates to an apparatus and method for finding an inoperative bulb in a series string of lights which becomes inoperable when one bulb becomes inoperative. More particularly, the present invention relates to providing a tester which is safe, is quick and is easy to use to determine which bulb or bulbs in the series circuit is inoperative so that the inoperative bulb may be replaced and the series string of lights returned to an operative state. The present invention further relates to a circuit tester which is economical to produce and safe to prevent a person from coming in contact with an exposed electrode. In addition, the tester can be used to check the polarity of 120 volt AC outlets and other electrical devices such as lamps.
2. Description of the Prior Art
Strings of Christmas lights are used to decorate during the respective season. Usually, individuals decorate using many multiples of series strings of lights to provide an impressive and decorative effect to show enthusiastic support for the holiday. However, due to the nature and quantity of the strings of lights used, prolonged illumination, physical abuse and inexpensive manufacturing, there is a relatively high frequency for bulbs to burn out, break and to just not work, possibly due to bad contact or other phenomena. It therefore becomes necessary to determine where the series string of lights is "broken", meaning where there is a break in the circuit which prevents operable lights from illuminating due to at least one bulb having become inoperable.
Prior to the present invention there have been many attempts to provide a circuit tester for use in determining the position of a break in a series string of lights. However, none of the previous circuit testers have overcome some significant problems within the prior art. In particular, none of the prior art circuit testers provide a simple, straight forward and safe circuit tester which does not require a battery, which does not require the operator to encounter an exposed wire, which does not require the operator to repetitively plug and unplug the tester from an electric outlet while performing the test, and which does not require the operator to remove the bulb from the socket in order to perform the test.
For example, U.S. Pat. No. 3,760,266, to Ocasio et al., discloses a single lead, plug-in type circuit tester having a bare lead which is inserted into one of the light sockets of a series string of lights to attempt to cut the inoperative bulb out of the circuit and by process of elimination pinpoint which particular bulb is inoperative. However, the Ocasio et al. device requires that, prior to testing the string, the operator first properly orientate and plug the circuit tester's plug prongs into the wall outlet socket so that the particular light socket of the series string being probed by the tester's bare lead forms a circuit with the tester. Ocasio et al. teach that the circuit tester first be used to probe a light socket of a series string of lights which is known to be in proper working order so that the circuit tester's plug may be properly oriented in the wall outlet socket before an inoperative series string of lights may be properly tested. Thus, if the Ocasio et al. indicator light goes on, then the circuit tester is properly orientated and correctly plugged into the wall outlet socket. If, however, the indicator light of the circuit tester does not go on, since the series string of lights is known to be in working order, the prongs of the circuit tester's plug must be switched to the opposite position in the prong receptacles of the wall outlet socket and only then can the circuit tester be used to properly probe and test an inoperative series string of lights.
Additional devices have been developed to overcome some of the shortcomings of the Ocasio et al. reference, but have resulted in problems of their own. U.S. Pat. No. 5,369,363, to Hey, discloses an implement for removing, installing and testing Christmas light bulbs which combines the features of a device for carefully and safely removing the bulbs from the series string of lights and testing the individual bulb utilizing power supplied from a battery in the handle of the device. However, the above description alone clearly shows the inherent drawbacks associated with using such a device. The device requires the operator to remove, test, and install, possibly, every bulb on a series string of lights before the inoperative bulb is ultimately found. Additionally, the Hey device is not capable of determining whether there is a break in the wire of the series string of lights, but instead merely only detects inoperative bulbs. The Hey device is slow, inefficient, expensive to manufacture and requires the operator to use a battery, which is problematic in itself if the operator does not have the required type of battery available and properly charged. The same can be said for the light bulb tester disclosed in U.S. Pat. No. 5,179,339, to Volk, Jr., which also requires the use of a battery and has exposed probes. Other examples of patents utilizing batteries in a series light string tester are set forth in column 1 of U.S. Pat. No. 5,319,312, to Segilia, which details many other types of series light string testers.
The Segilia reference is concerned with providing an apparatus for locating an inoperative bulb in a string of lights and in particular with providing a device which can be plugged into a bulb socket in the series string of lights and will indicate the particular direction within the string where the inoperative bulb is located. However, the Segilia reference teaches a device which requires that the bulb be removed from the socket and that the tester be inserted therein, a process which requires significant time, effort, patience, and also requires that the tester properly adapt to the type of socket. This can be a problem since series strings of lights from different manufacturers can have differently configured sockets. Furthermore, the Segilia apparatus requires a battery which, as stated above, is problematic.
Thus, the prior art requires devices wherein the operator must either utilize a battery with the device in order to avoid problems associated with standard outlets, or the operator must remove each bulb of the string of lights in order to find the inoperative bulb and in the case where the wire itself is defective and not a bulb, many of the prior art devices will not provide information to the operator to make such a determination.
Thus, there has long been a need for a circuit tester for use in determining where, in a series string of lights, there is an inoperable bulb or break in the wire, which is easy to use, inexpensive, and simple to manufacture, which has electricity supplied thereto by a plug which is plugged into any standard electrical outlet or socket, which incorporates a switch for toggling between a lead from each pole of the outlet supplying 110-120 alternating current, typically found in most American homes and businesses, and which protects the operator from coming in contact with any exposed, electrically conductive leads during testing.